Formation testing apparatus



2 Sheets-Sheet l Filed June 26, 1953 March 12, 1957 J. E. WALSTROM2,734,786

FORMATION TESTING APPARATUS Filed June 26, 1953 2 Sheets-Sheet 2.

IIIIII IIIIII IIII I IIIIIII' .Im" A iI I INVENTOR JOHN E. WA TROM drillpipe in the hole.

United States Patent() FORMATION TESTING APPARATUS John E. Wals trom,Diablo, Califl, assignor, by mesne assignments, to California ResearchCorporation, San Francisco, Calif., a corporation of DelawareApplication June 26, 1953, Serial No. 364,463

4 Claims. (Cl. 166-3) The present invention relates to apparatus forwithdrawing fluid samples from earth formations traversed by a borehole, more particularly to apparatus for sampling fluid content of aformation through the side wall ofthe borehole traversing saidformation, and has for an object the provision of an improved apparatusfor ropen-hole 'samplingin si-tu of the fluids containedin earthformations by rupturing or piercing the formation while controlling thelateral thrust of a body member of a sampling device against theformation to be tested to maintain a seal therebetween, both before andduring 'at a considerable distance above the bottom of the bore hole.

Heretofore, suchoflbottom testing for fluid content has only beenpossible under somewhat limited circumstances.

One of the methods commonly used includes the use of a pair of full-holepackers positioned above and below thejformationto be tested.Thedifficulty with this type of testing, also known as straddle-packertesting,"lies in a small clearance available between thepackers and thewalls of the bore hole due to thelimitedexpandability of the packers. Incommercial practice, it has been found fthat'packers can only beexpandedin diameter about one inch, where the diameter of the hole is inthejrangeof seven to nine inches. Where the formation to be tested liesat a depth of several thousand feet, such small clearance introduces avery serious hazard of sticking the Another serious limitation in theuse offull-hole, strad- 'dle" packers lies in the fact that suchstraddle packers can only be set relatively near the bottom of the hole.

Where a formation of interest lies more than a very few hundred feet offbottom, it is generally necessary to 7 land a plug in the well borebelow the formation to, be

tested upon which the drill pipe may be seated in order to expand asingle full-hole packer above the test formation. In practice, it hasbeen found that a testing tool upon which a packer is run into the holemay slip off such a plug or the plug may be pushed down the hole, and insome instances theplug may leak. Additionally, it is not desirabletoplug the hole if total depth has not been reached in the drilling ofthe well. In some instances delayed testing until total depth has beenreached may render the formation subject to severe damage by mud, or theformation may be damaged by caving or sloughing,

while the drilling is continued. Thus, a potentially-productiveformation may be lost entirely if the formation is not testeduntil asubsequent date.

Alternativeto the foregoing methods of testing a formation is theso-called drill stem test in which at predeterminedintervalsthe'drilling tool is withdrawn and are- A rection of 'arrows3--3 inFig. 2.

Patented Mar. 12,1957

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normal drilling operation at regular depth intervals to drill a reduceddiameter hole. Subsequent reaming of the hole is required to reachfull-hole size. Furthermore, the predetermined depth interval may oftenprevent testing of a particular part of the interval, without setting ofbottom plugs.

The third alternative available heretofore in commercial practice, andby far the most expensive, involves the setting of casing in the wellbore with subsequent piercing of thecasing,'as in normal oil-wellcompletion practice. This method is so expensive that it isnormallyfollowed onlywhen the indications'of a producing formation areextremely good. On what is considered arnarginal show of oil orgas in"the well, the setting of casing and completion of the well to test theshow is often considered so unattractive that it is not employed.However, should the show have been improperly evaluated as beingmarginal, a valuable well or field may be abandoned.

In accordance withthe present invention there is provided an apparatusfor open-hole formation testing for fluid content which may be'used atany timeafter the drilling of a well by conventional drillingprocedures. Further, the formation fluid content maybe sampled inadequate volume to obtain a true representation of the fluid inaccordance with the invention by supporting the testing apparatusadjacent the formation on drill pipe. In a preferred form of apparatus,thebody member is provided with means for forcing a portion of the bodyinto engagement with the side of the bore hole, which includes apivotally-mounted leg-member adapted to engage the opposite side of thebore hole and so pivoted with respect to the body thatthe lateral thrustof the body member againstthe formation may be controllably adjusted byregulating the weight of .that portion of the drill pipe which issupported between the leg member and the portion of the body member incontact with the formation. Means for piercing the portion of the bodymember in engagement withthe formation, as wellas the formation, isprovided within the body of the testing .tool, and flow passages betweenthe formation and the drill pipe are provided to permit formation fluids.to rise tion'taken in conjunction with the accompanying drawings whichform an integral part of the present specification.

In the drawings, Fig. l is a diagrammatic representation of a preferredform of the present invention illustrating the manner in which thetesting tool is supported in the well bore and controllably brought intocontact with the formation whose fluid content is to be tested.

Fig. 2 is an enlarged cross-sectional view of the lower end of thetestingtool illustrated in Fig. 1.

i Fig. 3 is a side view of the, testing tool "taken in thedition ofarrows 6-6 in'Fig. 2 particularly illustrating the formation-engagingface portion of the testing tool and the means for piercing said faceand the adjacent format-ion.

Fig' 7 is a side elevation view in the direction of arrows 7+7 in Fig. 2particularly illustrating a preferred form of the face-engaging portionof the testing tool. a

With reference to the drawings, and in particular Fig. 1, there isillustrated a preferred form of apparatus for carrying out the presentinvention, in which a fluid sampling tool 10 for sampling the fluidcontent of a formation 1 1 traversed by bore hole '12 is adapted to besupported in the bore hole by a stand of drill pipe indicated generallyas 13, which, in turn, is supported by drilling derrick 14 includingtraveling block 15 and crown block 16 through cable 17. As will beunderstood by those skilled in the art, drill pipe 13 may be raised andlowered in the bore hole by cable 17 operating through traveling block15 and crown block 16 by reeling and unreeling the cable on drum 218.The weight of the drill pipe 13 is arranged to be recorded or indicatedby dead weight indicator 19, which is interposed between the anchormeans 20 and the deadwire 'line 21, which forms an extension of the endof cable 17 passing downwardly from crown block 16.

In accordance with the present invention, during rupture of theformation and withdrawal of fluid therefrom the weight indicating means19 and the pipe supporting means,

including derrick 14 and cable 17, provides a means for controlling thelateral thrust of the face or formationengaging portion of the body 26of the fluid sampling tool 10 against the wall of the bore hole. Thelateral thrust of face portion 25 against formation 11 is provided by acombination of the vertical weight of drill pipe 13 andlaterally-extending leg member 28. In the present arrangement, leg 28 ispivoted at 29 and brought into engagement with the wall of bore hole '12by spring member 30. The function of wedging leg 28, when the weight ontesting tool 10 is increased by decreasing the tension on pipe 13 andcable 17, is to exert a lateral thrust of predeterminable value betweenface 25 and the side wall of bore hole 12 opposite the formation whichis to be tested.

As more fully illustrated in Figs. 2, 6 and 7, the face portion 25 forengaging the formation whose fluid content is to be tested may comprisea plug member threadably engaging the body member 26, which is providedwith a chamber 36 for positioning an explosive for piercing theformation, such as shaped charge 37, in a portion 38 of plug 35 which isruptured or pierced by explosive detonation of charge 37. In thepreferred embodiment of the invention, portion 38 forms a hold-backplate to permit shaped charge 37 to increase its piercing depth intoformation 11 when detonated by the dropping of a go-devil through pipe13 to contact blasting cap 40. Prima cord which may be brought into firmcontact with the formation wall by piercing through the mud cake, asshown in Fig. 6, which normally surrounds the periphery of bore ,hole12. To assist in the ready removal and insertion. of

plug 35 into body member 26, plug 35 may be provided with aplurality ofspanner wrench-engag-ing holes 47. As mentioned hereinabove, tool 10,and. the face portion thereof, is brought into engagement with the sidewall of bore hole-12 with a controllable thrustbytthe vertical action ofthe weight of drill pipe 13 acting through wedging leg 28 and pivot 29by which leg 28 is connected to extension 51 of body member 26.

Since it is desirable to maintain as small as possible the totaldiameter of the drill pipe 13 and the testing tool run into hole 12,provision is made for maintaining the wedging leg 28 in a restrainedposition against the action of spring 30, as partially illustrated inFig. 2 and more fully shown in side elevation, Fig. 3. As illustrated inthese figures, leg 28, including the side wall engaging portion 50, isheld by a transverse pin 52 within the housing 51, which forms a lowerextension of body member 26. Pin 52 is of the shear type which may besevered by knife edges 53 being moved upwardly by bull-nose plug 55being raised against biasing spring 56 when the weight of the drill pipein body member 26 is brought to bear thereon by lowering the entire toolto the bottom of the drill hole. Upon severance of the shear pin 52,wedging leg 28 is forced outwardly into the position shown in Fig. 1 andpartially illustrated in Fig. 2 by biasing spring 30. 'A stop member 58may be provided above wedging arm 28 to prevent arm 28 from pivotingabove the horizontal in the event that a cavernous formation isencountered during the withdrawal of the tool from the well bore. Itwill be apparent that the length of wedging leg 28 may be made such thatthe tool may be employed even where cavernous formations are encounteredby extending the length of the 'leg. Y After completion of the test,provision is made for shutting oh? the communication between theformation and drill pipe 13 through fluid passageways 60 and 72 whichformed the ignition path between cap 40 and charge 37. Such shut-off ismade by rotation of collar member 61 which forms an upward extension oftesting tool 10 adapted to engage the lower end of drill pipe 13. Asparticularly illustrated in Fig. 2 rotatable collar 61 is securedthrough screw 62 to a ring member 63 fitted within an upwardly-extendingand flanged portion 65 of the body portion 26. Collar member 61 ispreferably provided with recessed portion of arc-like configurationadapted to engage a pin member 71, best seen in Fig. 4, mounted upon theupper end of extended portion 65 of body 26. By rotation of drill pipe13 and collar member 61 fluid flow passageway 72 in collar 61 may berotated into the dotted line position, designated as 73, before the toolis lifted to withdraw the face of the testing tool away from the sampledformation. d

In operation of the present invention, particularlylthe form thereofillustrated in the drawings, the testing tool 10 is assembled, asillustrated in Fig. 2, and run into the hole with the pipe 13 maintainedsubstantially dry. The tool is then lowered until the bottom of the wellbore is reached, at which time the weight of the drill pipesupported byderrick 14 is decreased as indicated on weight indicator 19, thereby toshear holding pin 52 to permit wedging leg 28 to rotate outwardly intoengagement with the wall of well bore 12. The pipe and testing tool arethen raised in the well until the tool is opposite the formation whosefluid content is to be tested, such as formation 11. At that time thecombined weight of the tool and drill pipe supported by derrick 14 andcable 17 is again decreased to a predetermined degree as measured byweight indicator 19. This action causes the lateral thrust between face25 and formation 11 to be increased to a degree adequate to assure afirm sealing between the face of the formation and the face of thetesting tool. A godevil is then dropped through drill pipe 13 todetonate blasting cap 40, prima cord 41, and charge 37. Upon detonationof these explosives the formation face is ruptured and the fluid flowpath through chamber 36, passageway 60 and 72 cleared for the upwardflowof fluid from within formation 11 into pipe 13.

After the passage of adequate time for fluid content to rise throughbody 26 into drill pipe 13, the drill pipe may be rotated in a clockwisedirection-as seen Figs. 4

and ,5, to close communication between passageways 72 and passageway 64)and the tool lifted to release the lateral thrust between the face ofthe formation and the portion of the body member in engagement therewithand the entire assembly withdrawn from the well for removal of the fluidsample.

From the foregoing detailed description, it will be apparent that inaccordance with the present invention there is provided a fluid samplingapparatus for testing the content of a formation traversed by a borehole, in which the contact between the body member and the formation maybe maintained through the application of a controllable amount oflateral thrust introduced by the vertical weight of the drill pipeacting through a side wall engaging leg both before, during, and afterthe piercing or 111pturing of the formation and the withdrawal of fluidsample from the formation.

Various modifications and changes in the foregoing apparatus will occurto those skilled in the art without departing from the scope of thepresent invention. In particular, the face-engaging portion of plug 35may be adapted to provide other forms of sealing faces particularlyadapted to the type of formation Whose fluid is to be sampled. It willalso be apparent that a plurality of face-engaging similar to the singleone illustrated in the drawings may be brought into contact with theface of the Wall simultaneously and fluid withdrawn through each of theface portions. While a shaped charge for piercing the formation has beenillustrated and described, other forms of gun perforating apparatus maybe employed which may be detonated by concussion or electrical energy.

Other modifications and changes may be made without departing from thescope of the appended claims, and all such modifications falling withinthe terms of said claims are intended to be included therein.

I claim:

1. Open-hole fluid sampling apparatus adapted to be lowered into an openbore hole on a length of drill pipe comprising a body member connectedto said drill pipe and movable relative thereto, said body member havinga laterally disposed face adapted to engage the side wall of an openbore hole, a wedging leg pivotally connected to said body member belowsaid laterally disposed face, said leg including biasing means forforcing the opposite end of said leg extending below said pivot pointinto engagement with the side wall of said bore hole opposite aformation whose liquid content is to be sampled, means for applying atleast a portion of the weight of said drill pipe to said leg to wedgesaid opposite end of said leg into engagement with said bore hole wallto pivot said body member about the point of engagement of said leg withsaid bore hole wall for forcing said face into firm engagement with saidbore hole wall, a sample-receiving chamber in said drill pipe, rupturingmeans for rupturing said face and said formation, and cooperating fluidpassage means in said body member and in said drill pipe forestablishing fluid communcation to said sample chamber from saidruptured face to permit flow from said formation through said rupturedface to said sample chamber, said communicating passage means beingadapted to be closed in response to relative movement between said bodymember and said drill pipe upon completion of the sampling to trap saidformation fluid in said sample chamber.

2. Open-hole fluid sampling apparatus adapted to be lowered into an openbore hole on a length of drill pipe comprising a body member connectedto said drill pipe and movable relative thereto, said body member havinga laterally disposed face adapted to engage the side wall of an openbore hole, a wedging leg pivotally connected to said body member belowsaid laterally disposed face, said leg including biasing means forforcing the opposite end of said leg extending below said pivot pointinto engagement with the side wall of said bore hole opposite aformation whose fluid content is to be sampled, means for applying atleast a portion of the weight of said drill pipe to said leg to wedgesaid opposite end of said leg into engagement with said bore hole wallto pivot said body about the point of engagement of said leg with saidbore hole wall for focusing said face into firm engagement with saidbore hole wall, a sampling-receiving chamber in said drill pipe,explosively-actuated rupturing means within said body member andadjacent said face for rupturing said face and said formation,cooperating fluid passage means in said body member and in said drillpipe for establishing fluid communication to said sample chamber fromsaid ruptured face to permit fluid flow from said formation through saidruptured face to said sample chamber, explosive cap means in the lowerportion of said sample-receiving chamber of said drill pipe, andexplosive cord means extending through said cooperating fluid passagemeans for connecting said cap means to said rupturing means, saidcommunicating passage means being adapted to be closed in response torelative movement between said body member and said drill string up oncompletion of the sampling to trap said formation fluid in said samplechamber.

3. Open-hole fluid sampling apparatus adapted to be lowered into an openbore hole on a length of drill pipe comprising a body member connectedto said drill pipe and having at least a portion thereof rotatablerelative to said drill pipe, said rotatable portion of said body memberhaving a laterally disposed face adapted to engage the side wall of anopen bore hole, a wedging leg pivotally connected to said rotatableportion of said body member below said laterally disposed face, said legincluding biasing means for forcing the opposite end of said legextending below said pivot point into engagement with the side wall ofsaid bore hole opposite a formation whose fluid content is to besampled, means for applying at least a portion of the weight of saiddrill pipe to said leg to wedge said opposite end of said leg intoengagement with said bore ho-le wall to pivot said body member about thepoint of engagement of said leg with said bore hole wall for forcingsaid face into firm engagement with said bore hole wall, asample-receiving chamber in said drill pipe, explosively-actuatedrupturing means within said body member and adjacent said face forrupturing said face and said formation, and cooperating fluid passagemeans insaid rotatable portion of said body member and in said drillpipe for establishing fluid communication to said sample chamber fromsaid ruptured face to permit fluid flow from said formation through saidruptured face to said sample chamber, said communicating passage meansbeing adapted to be closed by rotation of said drill pipe while saidrotatable portion of said body member is in contact with said bore holewall and upon completion of the sampling to trap said formation fluid insaid sample chamber.

4. Open-hole fluid sampling apparatus in accordance with claim 3including explosive cord means for igniting said explosively-actuatedrupturing means extending from said sampling-receiving chamber in saiddrill pipe to said rupturing means through said cooperating fluidpassage means, said cord means resisting rotation of said rotatableportion of said body member with respect to said drill pipe andpreventing rupture of said face by said rupturing means if said cordmeans has been severed by closure of said cooperating passage means byrotation between said body member and said drill pipe, and means forigniting said explosive cord means in said sample-receiving chamber ofsaid drill pipe.

References Cited in the file of this patent UNITED STATES PATENTS2,173,532 De Long Sept. 19, 1939 2,313,369 Spencer Mar. 9, 19432,528,883 Hayward Nov. 7, 1950 FOREIGN PATENTS 852,386 Ger-many Oct. 13,1952

